Ion implanters are advantageous because they allow for precision with regard to the quantity or concentration of dopants implanted into a workpiece, as well as to the placement of dopants within the workpiece. In particular, ion implanters allow the dose and energy of implanted ions to be varied for given applications. Ion dose controls the concentration of implanted ions, where high current implanters are typically used for high dose implants, and medium current implanters are used for lower dose applications. Ion energy is used to control the junction depth or the depth to which ions are implanted into a semiconductor workpiece.
It can be appreciated that given the trend in the electronics industry to scale down electronic devices to produce smaller, yet more powerful devices (e.g., cell phones, digital cameras, etc.), that the semiconductors and integrated circuits (e.g., transistors, etc.) utilized in these devices are continually being reduced in size. The ability to “pack” more of these devices onto a single semiconductor substrate, or portion thereof (known as a die) also improves fabrication efficiency and yield. It can be appreciated that reducing the energy of the ion beam may allow implants to be performed to shallower depths to produce thinner devices and enhance packing densities. It can also be appreciated that increasing the dose in shallower implants can facilitate desired conductivity, and that beam current of lower energy ion beams may have to increase to facilitate increased packing densities. In other instances, it may be desirable to use a higher energy beam to selectively implant ions relatively deeply into the substrate, so as to create volumes with varying semiconducting properties (e.g., diodes) and/or to tailor the field distribution between different regions or devices in the substrate. Presently different tools (e.g., medium current vs. high current implanters) are used for these different applications.
It can be appreciated that it would be desirable at least for economic reasons to have a single ion implantation system perform a wide range of ion implants in various manners. One form of scanning is electric scanning, wherein a voltage is applied across two electrodes to create an electric field that diverts or alters the path of the ion beam. Electric scanning can generally be performed with low power requirements, but may cause the beam to suffer from space-charge effects. Another form of ion beam scanning is magnetic scanning, wherein a magnetic field is generated through which the ion beam passes that diverts or alters the path of the ion beam. The magnetic scanner may be more costly, but does not suffer from the space-charge blow-up resulting from electric fields. Accordingly, there is a need to provide an arrangement that allows the benefits of both an electric scanner and a magnetic scanner.